Imaging lens apparatus

Abstract

An imaging lens apparatus comprises four lenses with refractive power by which lead the light from the object side to the image side: a first lens with a convex object-side surface and positive refractive power, at least one surface of the first lens is aspheric; an aperture stop set next to the first lens; a second lens which is a biconcave lens with negative refractive power, at least one surface of the second lens is aspheric; a third lens which is a positive meniscus lens with a concave object-side surface, both side of the third lens are aspheric; and a fourth lens which is a negative meniscus lens with a convex object-side surface, both side of the fourth lens are aspheric with at least one inflection point; and the imaging lens apparatus satisfy the conditions below: |1 / slope_S8|>0.9; −0.2<SAG_S8<0.1.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention generally relates to a photographing lens apparatus, and more particularly to a photographing lens apparatus having four optical lenses and suitable for small photographing device.[0003]2. The Related Art[0004]With the growth of the consumer electronic markets, the request for photographing module is also increasing. Particularly to the camera equipped in photograph phone, tablet computer and laptop, optical lens almost become the mainstream accessories. However, in order to be installed in the mounting body which itself becomes more and more slim, small and light, the photographing module must be compact accordingly. Besides, image quality and pixels of the optical lens are also important considerations for customers to choose.[0005]In order to improve the image quality, more and more electronic products use multi-lenses in their photographing module. However, the incident light would reflect on t...

AI Technical Summary

Benefits of technology

The present invention provides an imaging lens apparatus that can eliminate or reduce ghost and flare caused by multiple reflection of multiple lens surfaces at the imaging area. By designing the aspheric surface of lenses to reduce reflected light between surfaces and keeping the distortion aberration under 2%, angle of view more than 70 degree, to correct the spherical aberration, chromatic aberration, astigmatic difference and the ghost, the imaging lens apparatus improves image quality and reduces produce cost.

Problems solved by technology

When a strong beam enters the photographing module, the reflected light arise from multiple reflecting surfaces each other could cause the flare and ghost at the imaging area.

Although the reflect impact of the lenses could be reduced by coating the lenses, said flare and ghost still cannot be completely eliminated when the incident light is too strong or the incident angle of said incident light is too large.

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